I have native query like below
SELECT ‘Free’, count(location) FROM warehouse WHERE pallet_id IS NULL
UNION
SELECT ‘Used’, count(location) FROM warehouse WHERE pallet_id IS NOT NULL
Then I can have pie chart to see “free space in warehouse”.
Is it possible to get same result using custom question (and customer expression) ?
Hi @CZvacko
Yes, for the databases that supports it - full outer join:
https://www.metabase.com/docs/latest/users-guide/custom-questions.html#joining-data
Hi @flamber
DB is MySQL, it doesn’t support it.
So, no other way and have to stay with native query, right ?
I just played with MSSQL DB that supports full outer join (warehouse self-joined like: where RowId=RowId). But I still don’t know how to define “Sumarize”, to get 2-rows answer applicable to pie chart.
@CZvacko I think you could probably do what you want with Custom Expressions:
https://www.metabase.com/blog/custom-expressions/index.html
But it's not possible to compare to a null value in functions:
Cannot use Custom Expression on boolean columns · Issue #12393 · metabase/metabase · GitHub - upvote by clicking 
on the first post
You would do something like this (if you have some other way of not using null):
@flamber
Ok, null is issue…
BTW, I can’t find case in 0.36.1, no matter what DB is used for question 